1. Field of the Invention
The present invention is generally directed to the field of semiconductor processing, and, more particularly, to using a rapid thermal anneal process to control the drive current of a transistor.
2. Description of the Related Art
By way of background, FIG. 1 depicts an illustrative NMOS field effect transistor 10 formed above a surface 14 of a semiconducting substrate 12 between trench isolation regions 25. The transistor 10 is comprised of a gate dielectric 16, a gate conductor 18, a plurality of sidewall spacers 20 and source/drain regions 28.
In the design of modem transistors, a parameter known as drive current (I.sub.D) is a significant parameter. In general, the drive current is the amount of current flowing through a transistor when it is turned "ON", i.e., when the proper voltage is applied to the gate conductor 18 of the transistor 10. However, the drive current of a transistor is affected by the physical dimensions of a transistor or some of its components, e.g., the nominal channel length "L", which is roughly equivalent to the width of the gate conductor 18, the width of the sidewall spacers 20, and the thickness of the gate dielectric 16, etc. For example, all the other things being equal, the larger the channel length, the slower the transistor will operate. Similarly, the thicker the gate dielectric, the slower the transistor will operate.
During the course of manufacturing a transistor, the size of the various components of the transistor, as actually built, may vary from the anticipated or design size of the components. As a result, transistor performance, as well as integrated circuit devices incorporating such transistors, may be adversely impacted. For example, assume that a gate conductor 18 is formed to a width greater that its design width, this will result in the channel length of the transistor being greater that anticipated. As a result, the transistor will operate at a slower speed. When this occurs to many of the thousands of transistors formed on an integrated circuit device, the overall operating speed and efficiency of the integrated circuit device may also suffer. What is desired is to have a method for manufacturing transistors, and integrated circuit devices incorporating the same, that helps to maintain device performance within acceptable limits. In particular, it is desirable to have a method of compensating for variations in the manufacturing process that may adversely impact the drive current of the transistor.
The present invention is directed to a method of making a semiconductor device that minimizes or reduces some or all of the aforementioned problems.